It is surprising to me that Google hasn't made the top bar/tray customisable. You can replace your lock screen, home screen, and keyboard but you're always stuck on the OEM provided notifications tray regardless...
I'd love to be able to install something and receive a completely different experience. Right now it is always just a piece meal of a potential experience.
PS - I installed Arrow. So far I like it. I'll give it a spin for a week (or until it annoys me).
I want something like a Firefox for launchers, with the same kind of addon support - replace any UX element, any animation, any function, add new ones, disable what you don't want, inject hooks where you like them, etc...
I'd love to see a notification tray that's customizable with widgets, search bar & voice control, custom toggles, context dependent adjustments (per-app or per-location quick settings and widgets, etc), IR remote control quick access, intelligent sharing menu (share screenshot / current open file / location / whatever), etc...
So far nobody has really gone for the whole scriptable sandbox approach. Mostly just layout customization over anything else.
I don't think it's possible to replace the lock screen in a native way. All "custom lockscreens" in existence today are basically hacks -- you will notice flickers when the lock screen activity is initialized, for example.
It's necessarily not customizable for some security reasons (unlock code, etc.)
I'd love to be able to install something and receive a completely different experience. Right now it is always just a piece meal of a potential experience.
PS - I installed Arrow. So far I like it. I'll give it a spin for a week (or until it annoys me).